All living things are composed of different kinds of cells. Each cell is very small and cells build up the organism. Both plant and animal cells contain a nucleus that controls the working of the cell. The nucleus contains the genes that are passed on from one generation to the next.

Plant cells contain green chloroplasts that trap the energy from the Sun and produce food for the plant by the process of photosynthesis. Both plant and animal cells contain vacuoles, or fluid-filled spaces. Plant cells contain large permanent vacuoles that are filled with a sugary liquid. Animal cells, if they contain vacuoles, have only temporary ones.

Both cells contain a jelly-like substance called cytoplasm. Both types of cell have a very thin skin around them, which is called a cell membrane. Waste products can pass out of the cell through the membrane and food and oxygen can pass into the cell. Only plant cells have a cell wall around the outside that gives the cell a rigid structure. Chloroplasts in a plant cell contain the green chemical chlorophyll. This is where photosynthesis takes place.